Document Type thesis Author Name Hsu, Chen-Ming URN etd-0429103-165607 Title Electrospinning of Poly(£`-Caprolactone) Degree ME Department Materials Science & Engineering Advisors Satya Y. Shivkumar, Advisor R.D. Sisson, Jr., Department Head Bar-on, Isa, Committee Member Keywords electrospinning Date of Presentation/Defense 2003-04-28 Availability unrestricted
The objectives of the present work are to produce porous polymeric scaffolds with Poly (ƒÕ-Caprolactone), PCL, by electrospinning. The structure in the electrospun polymer has been characterized by scanning electron microscopy. The effects of process variables such as voltage, solution concentration and deposition distance on the structure have been studied. The physical phenomena associated with the electrospinning process have been highlighted through high speed digital photography. The feasibility of using additives to the solution to control the structure of the porous construct has been examined. The data indicate that a range of structural morphologies can be produced in the electrospun polymer. Solid and hollow sub-micron beads can be produced by electrospraying of dilute solutions. Beyond a critical solution concentration of about 4 wt% PCL, elongational flow stabilizes the fibrous structure and a web of interconnected sub-micron fibers may be obtained. The average fiber diameter increases with concentration. A combination of elongated beads and fibers, known as the bead-on-string morphology is also observed under many conditions. The fibrous structure is stabilized at high voltages. The fiber diameter in the electrospun polymer typically exhibits a bimodal distribution. The addition of DMF (N,N-dimethylformamide) to the solution increases the deposition rate significantly and leads to extensive splaying, thereby reducing the fiber diameter to about 150 nm. DSC data indicate that electrospinning may lower the degree of crystallinity in the polymer. The wide of range of structural characteristics that may be obtained in the electrospun polymer make it suitable for many biomedical applications including medical textiles, drug delivery, membrane separation, tissue engineering and organ regeneration.
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